'Tonia' originates from Latin, specifically the word 'Antonia', where 'Antonius' was a Roman family name of uncertain (likely Etruscan) origin.

'Tonia' changed from the Latin feminine name 'Antonia' (the feminine of 'Antonius') and, through medieval and modern diminutive and short forms in languages such as Italian and English, became the modern given name 'Tonia'.

Initially it indicated belonging to the Antonius family (a family or clan name), but over time it evolved into its current use as a standalone female personal name.